Billionaire financier George Soros has thrown his money behind California's marijuana legalization measure with a $1 million donation a week before the vote.

The contribution reported Tuesday by The Sacramento Bee is the single biggest donation from an individual other than Oakland medical marijuana entrepreneur Richard Lee, the main sponsor of Proposition 19.

Soros, a high-profile liberal, was one of the top financial backers of the 1996 measure that made California the first state in the nation to legalize marijuana for medical use.

The $1 million comes a day after the Yes on 19 campaign launched its first television ad.

Until now, neither side has seen a huge outpouring of cash, though supporters have significantly out-raised opponents.